Linear Elasticity of Cubic Phases in Block Copolymer Melts by Self-Consistent Field Theory

• Published in: Macromolecules Vol. 36; no. 10; pp. 3764 - 3774
• Main Authors: Tyler, Christopher A, Morse, David C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 20.05.2003
• Subjects: Applied sciences; Exact sciences and technology; Mechanical properties; Organic polymers; Physicochemistry of polymers; Properties and characterization; Elastic modulus; SCF method; BCC lattices; Diblock copolymer; Temperature effect; Theoretical study; Dynamic elastic modulus; Modeling
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma0256946

We examine the linear elasticity of the bcc and gyroid phases of block copolymer melts with self-consistent field theory (SCFT). Linear elastic moduli for single crystals are predicted by calculating the free energies for slightly deformed crystal structures. Predicted Voight and Reuss bounds for the shear modulus of a polycrystalline material are quantitatively compared to the cubic plateau moduli found in linear viscoelastic measurements of both phases with good agreement. We also consider a model of pairwise additive interactions between “micelles” in the bcc and fcc phases and find that it predicts ratios of elastic constants consistent with those predicted by SCFT for the bcc phase, but not for the fcc phase.